Having looked at their website, I noticed that there is very little html text on each page - at least 60% of text is contained in

images. Added to that the target keywords/most important information is image based text.

I've been Googling to find confirmation that this is not a good practice, since I would assume google cannot understand the context of each page in order to determine relevance to keywords and ad text and to attribute quality score (and increases page load time - also bad for QS).

I know image based text is bad for organic SEO, but surely its just as bad for paid search campaigns and will impact quality score? Would be good to find some proof or confirmation that this is the case before suggesting they rebuild their website.

Re: image based text on landing page hurts quality score?

Yes, image based text can hurt your quality score. But only to the extent that Google will not be able to read the text that is in the image.

As you noted, image based text is not optimal for a lot of reasons other than affecting your QS. It makes your page load slower and is not considered as text when indexing the site.

But there is good news. All you really need to do is include that text in the alt attribute of the image tag. Google not only considers this to be a part of the page content, it gives that text a little extra weight. The same goes for title attribute of your links and anchors. Text in that title attribute gets extra weight from Google, for both organic and paid search ranking. Also, don't forget to include the meta description tag. Google will show this text in search results when relevant, and it is also used when indexing. Do not just stuff keywords in the description. The text should written as sentences and describe the content on the page. Do not use the same description on every page. Dont' even bother with the meta keywords tag, Google ignores it.

If the image has a lot of text, it may be difficult to do this. Web designers do this to get absolute control over the layout of their pages without dealing with the vagueries and differences between browsers, completely ignoring the factors we have both discussed here. Personally, I think it is ego-centric, lazy and a waste of resources.